You will see the option in the left-hand sidebar if you have a Sponsored Brand Ad in Seller Central (If you do not have any SB ads, you will not see the option). SB Ad Reporting allows you to see how your campaigns are performing from within the Advertising Center. 

“In order to make use of the SB ad position as a seller, you first need to complete the Brand Registry and have your products properly associated with the brand. You can only create Sponsored Brand Ads as a seller for products for which you are the brand owner.”  

The campaign information is organized similarly to your Sponsored Product Ads, but you will notice that a few fields are missing. This is expected, Sponsored Brand Ads do not have the same parameters / metrics. Additionally, it is important to note that at the moment, we cannot push any changes to SB ads within the Advertising Center through Amazon’s API. Once this functionality is added at Amazon's end, we will update the Advertising Center.